You guys talking about throw out bearing? Why would this be affected. It was flywheel bolts on disc..

 

The pilot bushing is a metal ring that presses into the back of the crank to support the Transmission input shaft and to keep the whole clutch assembly from misaligning during clutch engagement/disengagement. We cannot see this bushing installed in the back of your crank from the pics you showed. Running sans pilot bushing can cause serious issues, including premature wear on tranny bearings.

 

Without it, the pressure plate may have deformed the clutch disc thus resulting in the carnage experienced. It could also be the reason there is a darker inner circle on flywheel than along its outer circumference. See what I mean?



For reference, a pic of a pilot bushing below.

 

Ya know, I had just assumed he already popped the old one out. It's one of the first things I do.

 

I dunno... if the OP says he did then that's fine and dandy. If it's MIA, then it's a potential contributor to the issue along with the flywheel's thickness.

OP, what say ye?

 

There seems to be an unusual amout of heat discoloration on both the flywheel and what we can see of the pressure plate. Was the clutch properly adjusted? Was the clutch slipping? Perhaps the pressure plate wasn't flat?

Looking at the clutch disc, it shows signs of excessive wear of the friction surface. The disc looks like it would have 100,000 miles on it, not 1,000. There is definitely something wrong there.

I would say the wear on the hub portion of the disc and the flywheel bolts would be due to a flywheel that is too thin, since the the disc and pressure plate register on the flywheel.

If the "shiny springs and bolts" are the only issues you should feel fortunate, given the other issues your pictures bring to light.

Good Luck.

Roger Carter

 

You guys may be onto something! I don't have a pilot bushing.

As for clutch wear it was in my 390 with about another 1000 k which looked mint. Flywheel was resurfaced.
I think the problem is 4 wheel this truck on 44's and clutch has got worked hard.
I'm looking into a semi ceramic clutch as this motor obviously has too much power and smoked the disc quickly.

Also I asked my shop if they measure thickness on a flywheel before a balancing job especially on a over 30 year old engine. Machinist said no! I said that sounds like it would be pretty common practice to check if its useable before doing work on it! Idiots. Anyway I'm taking flywheel to them in the next couple days so they can inspect it.

 

Running with no pilot bushing will allow the input shaft to droop if the transmission is worn... Secondly when the clutch is in contact there is no guarantee that the disk is centered. You MUST get a pilot bushing installed in that crank.

The clutch likely isn't the culprit and the 390 likely doesn't have too much power. If it is slipping it is either not adjusted properly OR you have not enough gears for 44 inch tires. 5.13 is kinda the least it should be. 5.86 or 6.17 might be more in order if you are wheeling it hard. Big tires....deep muck or steep hills will need all the ratio you can get. 6.17 would only be turning 2800 rpm at 60 mph which would be about right for a 390

Your order of business should be :

New pilot bushing, Inspect flywheel for minimum thickness and resurface if possible. Keep in mind that the lighter the flywheel is, the less rotating mass you have to get 44's turning. IF it has been ground a number of times replace it. Counterboring the crank bolts is only going to allow you to use a fly wheel that is too thin with too little mass to absorb and dissipate heat. I'd try to run the heaviest flywheel you could lay your hands on. I'd scrap that disk and possibly the pressure plate. If it has been hot enough to blue the wheel...the pressure plate is likely been hot and blue too. It will chatter. The disk is not safe as the retainers for the springs are torn up. If you crack out the disk hub you'll be pulling this out again. Chances are if it has been wobbling like I assume it has..the hub splines are likely sloppy now.

Check your input shaft nose for damage. It should be smooth and shiny. If it is damaged at all it will eat your pilot bushing. Check the input shaft for excessive play and or bearing noise. Running it off center all this time isn't good for it. If it all checks out, reassemble it and give it about 1.5 to 2 inches of free play at the pedal. You want it disengaging down at the floor....not way up at the top. Too little free play will cook that clutch as it wears. A little wear...the free play is gone and it begins to slip. You are better to have MORE free play than too little. I see a lot of trucks with it adjusted up at the top. Maybe guys with short legs .

Check your transmission input shaft sleeve where the throw out bearing rides. It should be nice and smooth too. If it has excessive wear it can cause the throw out to hang up and allow the pressure plate to be partially disengaged. The throw out arm and pivot ball should move smooth as silk when you slide the throw out on the input sleeve.

.



Cheers
Mac.

 

Still reading above post but to be clear this is on my healthy .030 over 428 FE

 

Ok for gears I run 5:13's already. Any lower and the pinon gets small and weak.
As for trans I swapped it just yesterday as well ( well in place until clutch is resolved) for a f350 2wd unit with a 32 spline ,1350 yoke.
It's from a low mileage truck.
BUT my bearing retainer sleeve did break on this last one and had some scoring. I replaced with a good used one.
Anyways that's out.

Pilot bearing has been my issue all this time I guess. Don't think it ever had one from my 390 that I swapped to the now 428. Yes it's balanced to the rotating assembly .

This is why I post here. Thanks for all the help so far!!

 

I've got a centerforce clutch coming in on Thursday. I had another clutch disc kicking around and this one looks like it sits higher in center than the one on my bench out of another 78. Might of been wrong clutch.

 

Should have noticed that there were two pages and I only read page one. Looks like the issues have been discovered. Please ignore this post.